1. Technical Field
The present invention relates to a semiconductor package and a method of manufacturing a semiconductor package, and more particularly, a semiconductor package with bonding wires and a method of manufacturing the semiconductor package.
2. Description of the Related Art
As portable electronic devices become increasingly miniaturized, the demand for a reduced thickness semiconductor package has significantly increased. Thus, a type of semiconductor package, such as a multi-chip package (MCP), in which a plurality of semiconductor chips are embodied on a substrate has been developed. Accordingly, the number of wires, which electrically connect a chip pad that is on a semiconductor chip with a finger that is on a substrate, have increased. On the other hand, the finger, which is formed on the substrate, needs to be relatively small, and thus, problems occur when the finger is bonded with the wires.
FIG. 1A is a cross-sectional view of a conventional semiconductor package.
Referring to FIG. 1A, a first semiconductor chip 30_1 is adhered onto a substrate 10 using an adhesion layer 20_1. A second semiconductor chip 30_2 is adhered onto the first semiconductor chip 30_1 using an adhesion layer 20_2. A first wire 60_1 is formed to electrically connect a first chip pad 31_1, which is on the first semiconductor chip 30_1, with a finger 11, which is on the substrate 10. A protrusion 62_2 is formed on one end of the first wire 60_1 so as to be formed on the finger 11, and a bump 64_1 is formed on the other end of the first wire 60_1 so as to be formed on the first chip pad 31_1. A second wire 60_2 is formed to electrically connect a second chip pad 31_2, which is on the second semiconductor chip 30_2, with the finger 11, which is on the substrate 10. A protrusion 62_2 is formed on one end of the second wire 60_2 so as to be formed on the finger 11, and a bump 64_2 is formed on the other end of the second wire 60_2 so as to be formed on the second chip pad 31_2.
FIG. 1B is a perspective view of protrusions 62_2 and 62_1 formed on the finger 11 of FIG. 1A, and FIG. 1C is a cross-sectional view of the protrusions 62_2 and 62_1 taken along line X-X′ of FIG. 1B.
Referring to FIGS. 1B and 1C, the protrusion 62_1, which is formed on one end of the first wire 60_1, and the protrusion 62_2, which is formed on one end of the second wire 60_2, are disposed on the finger 11. Generally, a protrusion is formed by applying a load to a protrusion ball formed around a tip of a capillary providing a wire onto the finger 11. When the substrate 10 is viewed along its normal direction, the shape of an upper surface 11a of the finger 11 is a quadrangle. The width of the upper surface 11a of the finger 11 measured along a short side is less than the diameter of each of the protrusions 62_1 and 62_2. However, the length of the upper surface 11a of the finger 11 measured along a long side is greater than the diameter of each of the protrusions 62_1 and 62_2. Accordingly, even if a load is applied to the protrusion ball, it is difficult for the protrusions 62_1 and 62_2 to be disposed below the upper surface of the finger 11. In addition, lateral surfaces 11c of the finger 11 do not contact the protrusions 62_1 and 62_2.
Hence, a protrusion formed on one end of a wire is bonded with a finger only at an upper surface of the finger, not the lateral surfaces of the finger. However, since the finger is relatively small, an area of the upper surface of the finger needs to be small also. Accordingly, since an electrical contact area is reduced, an electrical resistance between the protrusion and the finger increases. In addition, since a bonding area is reduced, a wire may easily separate from the finger due to physical impact and thus, product defects may occur.
The present invention addresses these and other disadvantages of the conventional art.